Method and device for compressing a substance by impact and plasma cathode thereto

ABSTRACT

A method of compressing a substance by impact in axisymmetric relativistic vacuum diodes (RVD) having a plasma cathode and an anode-enhancer including: producing an axisymmetric target of a condensed substance, which functions at least as a part of the anode-enhancer; axially placing said electrodes; and pulse discharge of a power source via the RVD. To compress a substantial portion of the target substance to a superdense state, a plasma cathode is used in the form of a current-conducting rod comprising a dielectric end element having the perimeter of the rear end embracing the perimeter of the rod in the plane perpendicular to the axis of symmetry with a continuous gap, and the area of the emitting surface being greater than the maximum cross-section area of the anode-enhancer; the anode-enhancer is placed towards the plasma cathode so that the center of curvature of the working surface of the anode enhancer is located inside the focal space of the collectively self focussing electron beam; and the anode-enhancer is acted upon by an electron beam with an electron energy not smaller than 0.2 MeV, current density not smaller than 106 A/cm2 and duration not greater than 100 ns.

FIELD OF INVENTION

This invention relates:

-   -   to a method for impact compression of a condensed (liquid or,        preferably, solid) substance to a superdense state in which        pycnonuclear processes and inertial confinement fusion (ICF        hereafter) may proceed, and    -   to a structure of devices based on relativistic vacuum diodes        (RVD hereafter) including plasma cathodes, designed for carrying        out the said method.

This technology is intended practically for transmutation of atomicnuclei of certain chemical elements into nuclei of other chemicalelements with the purpose of:

-   -   Experimentally obtaining preferably stable isotopes of chemical        elements including synthesis of stable transuranides;    -   Reprocessing radioactive waste containing long-lived isotopes        into materials containing short-lived isotopes and/or stable        isotopes, which is particularly important in decontamination of        used gamma-ray sources, e.g., based on radioactive isotopes of        cobalt widely used in industry and medicine.

In future, this method may be useful for obtaining energy by the ICFwith utilization of preferably solid targets.

For the purpose of this description, the following terms as employedherein and in the appended claims refer to the following concepts:

-   -   “target” is a once used for impact compression dose of at least        one arbitrary isotope of at least one chemical element, being a        raw material for obtaining products of nuclear transformations        and, optionally, a primary energy carrier for energy producing;    -   “impact compression” is an isoentropic impact action of a        self-focusing converging density wave on at least a part of a        target;    -   “superdense state” is such a state of at least a part of the        target after it has been compressed by impact, at which state a        substantial portion of the target substance transforms into        electron-nuclear and electron-nucleonic plasma;    -   “pycnonuclear process” is such a recombinational interaction        (‘cold’ in particular) between components of electron-nuclear        and electron-nucleonic plasma of the target substance compressed        to a superdense state causing at least the target isotopic        composition change;    -   “plasma cathode” is such a consumable axisymmetric part of the        RVD negative electrode which is able (in the beginning of the        discharge pulse) to generate plasma shell (of the material of        the near-surface layer) with the near zero electron work        function;    -   “anode-enhancer” is such once used replaceable axisymmetric part        of the RVD anode which may be completely produced of preferably        conductive (in the main) material and used as a target itself in        the simplest demonstration experiments, or has the shape of at        least a single-layer shell of a hard strong material inside of        which a selected target is fixed also axisymmetrically providing        the acoustic contact, when such anode-enchancer is used for        industrial needs;    -   “focal space” is such a volume in the RVD vacuum chamber which        spatially confines a certain length of the common geometric        symmetry axis of the RVD electrodes and in which (in the absence        of obstacles and under pre-set values of the area of the        emitting surface of the plasma cathode, energy of electrons and        current density) a pinch of electron beam is possible due to        collective self-focussing of relativistic electrons.

BACKGROUND ART

It is well known theoretically (see, e.g., U.S. Pat. No. 4,401,618) thatin order to carry out a controlled nuclear fusion, it is necessary andsufficient:

-   -   First, to make a target of a microscopic size, the mass of which        is usually of several micrograms to several milligrams,    -   Second, to fix the formed target in a space,    -   Third, to transfer a target substance into a superdense state by        as uniform as possible impact compression of the target,    -   Fourth, to hold the substance of the target in such state the        time enough for transmutation and/or nuclear fusion of atoms,        which can be accompanied by energy release or absorption.

Worth to be mentioned that said limitations of the target mass areimportant mainly for the ICF because 1 mg of deuterium or a mixture ofdeuterium and tritium has an energy equivalent of about 20-30 kg oftrinitrotoluene.

Also theoretically obvious is the fact that transmutation and/or nuclearfusion occur actually simultaneously with the attainment of a superdensestate. Therefore, the efforts of researchers in the field of nuclearphysics have been directed to the creation of most efficient methods andmeans for impact compression of substances so far.

And, finally, it is also theoretically clear that:

-   -   such a compression is possible only under the conditions of        generating a high-power mechanical impulse of the duration order        of several tens of nanoseconds and focussing this impulse onto a        substantial area (up to the whole) of the surface of a target        located in a securely isolated from the environment volume,    -   means for space-time compression of an energy flux are required        for that purpose, such as primary energy source, at least one        energy storage, at least one converter for transforming the        accumulated energy into a mechanical impact impulse, and a        mechanical striker for essentially isoentropic transfer of this        impulse onto the target,    -   the problem of a sufficient set of such means and interactions        between them can be solved in different ways depending on the        purposes of the experiments with the impact compression of a        substance provided that (when connected to an industrial power        network) the first but not the only energy storage is usually a        device based on a LC-circuit (see, e.g., collected articles:        Energy Storage, Compression and Switching, edited by W. H.        Bostick, V. Nardy and O. S. F. Zucker. Plenum Press, New York        and London).

For years, efforts to realize said theoretical assumptions in practicehad been directed only to the ICF the industrial mastering of whichseemed to be sufficient for the humanity to move to “energy paradise”.

For this reason, only gaseous deuterium or deuterium and tritium wereused as an active substance from the very beginning, and targets wereproduced in the shape of tight empty spheres filled with microscopic(about 0,1 mg) portions of said hydrogen isotopes. Then, the beams oflaser drivers were pointed at each such target uniformly andsynchronously from many sides.

Heating of the shell caused an ablation (partial evaporation) of itsouter portion. The expansion of the evaporated material was giving riseto reactive forces which caused implosion, i.e. uniform compression ofthe inner portion of the shell and active substance of the target in thedirection to the sphere center (see, e.g., (1) U.S. Pat. No. 4,401,618;(2) J. Lindl, Phys. of Plasmas, 1995; (3) K. Mima et al., Fusion Energy,1996. IAEA, Vienna, V. 3, p. 13, 1996).

This ICF scheme seemed to be irreproachable. Actually, the duration oflaser radiation pulses can be brought to about 1 ns. This could ensureefficient time compression of an energy flux, and a sharp decrease inthe target surface area could be a prerequisite for the spacecompression of said flux as well.

Unfortunately, the efficiency of lasers does not exceed 5%, that fromvery beginning made doubtable the effectiveness of the laser driver,taking into account Lawson criterion (J. D. Lawson, Proc. Phys. Soc.,B.70, 1957). Further, the synchronization of lasers switching requires asophisticated automatic control system. And, finally, the ablation isaccompanied with significant losses in energy for heating the shell andtarget as a whole. Thus, nobody has brought so far the gaseous substanceof the target to the superdense state and has got a positive yield ofenergy that could exceed the energy consumption for ICF initiation.

Known are the efforts to create the pressure and temperature sufficientto ignite fusion reactions by means of an acoustic driver, which must toinduce cavitation in condensed, liquid in particular, targets (U.S. Pat.Nos. 4,333,796; 5,858,104 and 5,659,173). Particularly, InternationalPublication WO 01/39197 describes:

-   -   (1) a cavitation fusion reactor comprising:    -   at least one source of mechanical supersonic oscillations,    -   preferably a plurality of sound conductors capable of        transmitting these oscillations into the confined body of a        target in a resonance mode with an increase in the energy flux        density per unit of area,    -   means for heat removal in the form of a suitable heat exchanger;    -   (2) such method of use of the described reactor, which includes:    -   producing targets poorly conducting sound by pressing a fuel        material required for nuclear fusion, preferably titanium        deuteride, or lithium deuteride, or gadolinium dideuteride,        etc., into a solid sound conducting matrix from a refractory        metal (e.g. titanium, tungsten, gadolinium, osmium or        molybdenum), introducing at least one such matrix with at least        one such target into acoustic contact with at least one sound        conductor connected to the source of mechanical supersonic        oscillations,    -   acting upon such matrix by a train of supersonic impulses in a        resonance mode, which acting causes mechanical-and-chemical        destruction of deuterides and fluidization of targets due to the        conversion of kinetic energy of the mechanical oscillations into        the heat and essentially simultaneously induces cavitation in        the ‘liquid’ targets due to ‘evaporation’ of deuterium from the        targets, i.e. appearance of vapor bubbles and their collapse        under the pressure of the host material, and    -   terminating the process after nuclear fusion reactions with        energy release inside the targets are completed.

Use of solid (in the initial state) targets and supersonic mechanicalimpulses for their impact compression seems to be rather attractive.Unfortunately, like lasers, the sources of ultrasound have insignificantefficiency. Moreover, unlike lasers, these sources yield rather smalldensity of power in the impulse, which makes it necessary to put thesystem ‘ultrasound source—deuteride target’ in the resonance mode.However, even in this mode, the major portion of energy is spent forheating targets and dissipates. Therefore, impact compression of thesubstance to a superdense state was not achieved even in case ofprolonged pumping of energy into the target.

Accordingly, the problem of creation of feasible methods and means forimpact compression of the substance to a superdense state remainsurgent.

Long-range approach to its solution is based on use of RVD known sincethe beginning of the 20^(th) century (see, e.g., (1) C. D. Child, Phys.Rev., V. 32, p. 492, 1911; (2)1. Langmuir, Phys. Rev., V. 2, p. 450,1913).

Each RVD comprises a vacuum chamber inside of which a cathode and ananode are fixed, said cathode and anode are connected to an electriccharge storage via a pulse discharger. With a sufficiently great chargeand a short duration of a discharge pulse, such diodes are capable ofproviding an explosive electron emission from the surface of the cathodeand acceleration of electrons to relativistic velocity with theefficiency of more than 90%.

Exactly in this function of generators and accelerators of powerfulelectron beams, the relativistic vacuum diodes had been the object ofattention of physicists during the whole 20^(th) century, and numerousenhancements to the design of such diodes as the whole and particularlycathodes for them were intended for the space-time compression of energyin the electron beams and shaping these beams to required spatial form.

An effort in creation of a method for compressing a substance by impactin the RVD for ICF is known from U.S. Pat. No. 3,892,970. This methodincludes:

-   -   First, producing a target in the shape of a symmetric pellet of        a condensed (preferably solid) substance from a frozen        thermonuclear fuel (i.e. deuterium or a mixture of deuterium and        tritium),    -   Second, placing the target between the RVD electrodes, in other        words, into the volume, into which the output of means for anode        plasma generation is opened, and    -   Third, practically synchronous injection an anode plasma and        compression of the target with impulse (at 10 ns) annular impact        by means of short-circuit of a powerful current (the order of        100 TW and the energy of 1 MJ) via the anode plasma.

However, such method does not provide the compression of the targetsubstance to a superdense state and holding it in such state long enoughfor nuclear fusion with energy release because the size of the target isobviously smaller than the path length of the electrons with the energyof about 1.5 MeV. That is why the kinetic energy of electronspractically immediately converts into thermal energy in the whole bodyof the target causing a spatial thermal explosion of the nuclear fuel.Further, it is extremely difficult in the known method to synchronizehitting of the freely flying target into the center of an annular RVDcathode with the discharge of the source of energy and producing a flatplasma anode. Accordingly, focussing of the electron current on thetarget can be achieved only occasionally despite of adjusting thedischarge voltage and the anode plasma density.

An RVD based device for impact compression of a substance, known fromthe same patent, comprises a spherical vacuum chamber fitted with a heatexchanger and provided with a channel for targets feeding, two annularcathodes located symmetrically with respect to the central plane of thevacuum chamber, additional plasma injecting device located between thecathodes and forming a flat plasma anode directly prior to the dischargeof the supplying circuit.

And finally, the known from the same patent cathode has a currentcarrying part and a focussing tip made in the shape of a ring with asharp edge for increasing an electric field gradient thereon. The edgeof such cathode is covered with its own layer of plasma during adischarge.

It is actually impossible to transfer a tangible portion of energy ofthe annular electron beam to the target in such RVD, because the beam isalready on the pinch threshold at the very moment of its formation andis unstable (especially in combination with such plasma anode, whichparameters change essentially both during each pulse and from one pulseto another).

Therefore, it is desirable that the anode should be made from solidsubstance and either itself functions as a target or incorporates atarget, and that the pinch should be prevented in the gap between theelectrodes and self-focussing of the electron beam be achieved on theanode surface simultaneously in the process of the discharge.

It is astonishing, that, according to the available data, main attentionin development of such means was paid only to shaping the RVD cathodeemitters while using essentially flat anodes. A striking example of suchapproach can be a RVD based pulse source of electrons that comprises aplasma cathode having a shaped plate of a dielectric material and aconductive cover of precisely the same shape for a portion of thesurface of said plate (SU 1545826 A1). Under a pulse discharge, such acomposite cathode can generate an electron beam, which is not subject tothe pinch and has the shape that corresponds to the shape of thedielectric plate.

However, such as much as possible uniform compression of the target,which is necessary for the ICF and pycnonuclear processes, isunachievable by shaping the electron beam only. Therefore, the describedRVD and its analogues can not be feasibly applied in the processes ofimpact compression of a substance up to a superdense state.

Problems in suppressing the pinch in the gap between the electrodes andin providing the self-focussing of electron beams on the target surfacemade many physicists so pessimistic that they came to a conclusion ofprincipal inapplicability of RVD's as drivers for transmutationprocesses and ICF (see, e.g., (1) James J. Duderstadt, Gregory Moses,Inertial Confinement Fusion. John Wiley and Sons, New York, 1982. (2) E.P. Velikhov, S. V. Putvinsky. Fusion Power. Its Status and Role in theLong-Term Prospects. In 4.2.2. Drivers for Inertial ControlledFusion/http://relcom.website.ru/wfs-moscow. etc).

Nevertheless, the research in this direction continued.

Thus, the nearest to the invention, as for the technical essence, methodand means that are in principle applicable for impact compression of asubstance were disclosed at International Conference dedicated toparticle accelerators (S. Adamenko, E. Bulyak et al. Effect ofAuto-focusing of the Electron Beam in the Relativistic Vacuum Diode. In:Proceedings of the 1999 Particle Accelerator Conference, New York, 1999)and in a later article (V. I. Vysotski, S. V. Adamenko et al. Creatingand Using of Superdense Micro-beams of Relativistic Electrons. NuclearInstruments and Methods in Physics Research A 455, 2000, pp. 123-127).

Method of impact compression of a substance, which can be easilyperceived by those skilled in the art from the above-mentioned sourcesof information, includes:

-   -   producing a target in the shape of such an axisymmetric part        from a condensed substance that is at least a part of a RVD        anode (namely, in the shape of a hemispheric tip of a        needle-like anode-enhancer having a diameter of the order of        several micrometers),    -   placing the target in the RVD fitted also with an axisymmetric        plasma cathode, which is located practically on the same        geometric axis with said anode-enhancer and is spaced by several        millimeters therefrom, and    -   pulse discharge of the power source via the RVD in the        self-focussing mode of an electron beam on the surface of the        anode-enhancer.

Device using the described method for impact compression of a substancewas made on the basis of a RVD. It comprises:

-   -   a strong gas-tight housing a part of which is made of a        current-conducting material shaped in axial symmetry to confine        a vacuum chamber, and    -   an axisymmetric plasma cathode and an axisymmetric        anode-enhancer fixed in said chamber practically on the same        geometric axis of which at least plasma cathode is connected to        a pulsed high-voltage power source.

The cathode was made in accordance with a classical scheme:‘current-conducting (usually metallic) rod converging in the directionto the anode ended with dielectric element’, the perimeter and the areaof the operative end of the latter element being no greater than therespective perimeter and the cross section of said rod (Mesyats G. A.Cathode Phenomena in a Vacuum Discharge: The Breakdown, the Spark andthe Arc. Nauka Publishers, Moscow, 2000, p. 60).

Shaping the both electrodes in the specific geometric forms allowed thepinch to be suppressed in the RVD gap, and to sharpen the electron beamto provide it's self-focussing on a small portion of the surface of theanode-enhancer.

However, such essentially point action on the anode-enhancer is suitableonly for demonstration of the RVD applicability for impact compressionof a substance, but it cannot provide the compression of a substantialportion of the target body to a superdense state at each pulsedischarge.

BRIEF DESCRIPTION OF THE INVENTION

Therefore, the invention is based on the problem:

-   -   First, by way of changing the conditions of performing the        steps, to create such a method for impact compression of an        essential portion of the target substance to a superdense state        that could be fulfilled at each pulsed RVD discharge,    -   Second, by way of changing the shapes and relative positions of        electrodes in RVD, to create such a device for compressing a        substance by impact, which would ensure effective application of        the method, and    -   Third, by way of changing the shapes and dimension ratios of        conductive and dielectric parts, to create such an axisymmetric        plasma cathode which would provide the most economic effective        application of the method.

The first aspect of the problem is solved so that in the method ofcompressing a substance by impact using a RVD having an axisymmetricvacuum chamber with current-conducting walls, an axisymmetric plasmacathode and an axisymmetric anode-enhancer, including:

-   -   producing a target in the shape of an axisymmetric part of a        condensed substance that functions as at least a part of the        anode-enhancer,    -   placing the anode-enhancer into the RVD chamber with a gap        towards the plasma cathode practically on the same geometric        axis therewith, and    -   pulse discharge of the power source via the RVD in the electron        beam self-focussing mode on the surface of the anode-enhancer,        according to the invention    -   the axisymmetric plasma cathode is used in the form of a        current-conducting rod comprising a dielectric end element        having the perimeter of the rear end embracing the perimeter of        said rod at least in the plane perpendicular to the axis of        symmetry of the cathode with a continuous gap, and the area of        the emitting surface being greater than the maximum        cross-section area of the anode-enhancer,    -   the anode-enhancer is placed with such a gap towards the plasma        cathode that the center of curvature of the working surface of        the anode-enhancer is located inside the focal space of the        collectively self-focussing electron beam, and    -   the anode-enhancer is acted upon by an electron beam having the        electron energy not less than 0.2 MeV, current density not less        than 10⁶ A/cm² and duration not greater than 100 ns.

The results of application of this method happen to be quite unexpectedeven for the inventor who had been striving for them more than 10 years.Thus, using the simplest monometallic targets of highly pure copper,tantalum and other materials enabled to demonstrate experimentally thefollowing:

-   -   after being compressed by impact, a tangible portion of each        target mass flew apart and precipitated as aggregates of        transmutation products on the walls of the RVD vacuum chamber        and/or on a shield mentioned below;    -   some aggregates were rather homogeneous as for their elemental        composition;    -   in the aggregates were certainly detected not only stable        isotopes of known chemical elements which had not been present        in the substance of the targets as admixtures but also        relatively stable isotopes of unknown now and not yet identified        transuranides;    -   isotopic composition of the products of transmutation of the        target substance essentially differed from the reference data on        the isotopic composition of the same elements in the Earth's        crust,    -   the attempts to detect positive yield of thermal energy from the        zone of transmutation failed up to now.

The above distinguishes the transmutation according to the invention inessence from the traditional transmutation attained by bombardment ofsolid targets (e.g., made from the same copper or molybdenum) by ions(deuterons as a rule) produced from sources with magnetically confinedanode plasma and run in complicated and dangerous in operation pulseaccelerators to obtain power fluxes of the order of 1 kW at the ionenergy of more than 5 MeV (see, e.g., U.S. Pat. No. 5,848,110). In fact,only known in advance mainly radioactive isotopes of known in advancechemical elements, e.g., Zn⁶⁵, Mo⁹⁹, I¹²³, O¹⁵, etc. can be produced insuch processes, whereas the method according to the invention isapplicable at least for fusion of transuranides in quantities sufficientfor chemical study.

Mentioned above and described in detail below results of carrying outthe method according to the invention allow to suppose that the electronbeam is collectively self-focussing on a essential portion of thesurface of the anode-enhancer and excite in its near-surface layer amechanical soliton-like density impulse converging to the symmetry axisof the target. This impulse transmits in the isoentropic manner theenergy received from the electron beam to a portion of the targetsubstance near its symmetry axis. The leading edge of said impulse tendsto a spherical form. Therefore, as the soliton-like impulse reduces to acertain small volume with the center on the target symmetry axis, itsleading edge becomes steeper, and the density of energy thereinincreases to a magnitude sufficient for the substance to reach asuperdense state enough for pycnonuclear processes to proceed. That isthe reason why the simplest (and, what is very important, practicallysafe in operation) RVD type electron accelerator with a minimum powerconsumption provides (as will be shown in detail below) thetransmutation nuclear reactions with the yield of a wide spectrum ofisotopes.

The first additional feature consists in that used in the relativisticvacuum diode plasma cathode has a pointed current-conducting rod, thedielectric end element of this cathode is provided with an opening forsetting on said rod, and the setting part of said rod together with thepointed end is located inside the opening. This allows to control atleast partially the gap between the RVD electrodes and to stabilize theplasma cathode operation, that is especially important for experimentaloptimization of the impact compression process.

The second additional feature consists in that the target is formed inthe shape of an insert into the central part of the RVD anode-enhancer,the diameter of said insert is chosen in the range of 0.05 to 0.2 of themaximum cross-sectional dimension of the anode-enhancer. This allows touse any material as an object of compression to a superdense stateirrespective of its electric conductivity and its usage both in a solidand a liquid state. Naturally, a liquid should be encapsulated eitherdirectly in the solid shell of the anode-enhancer or in an individualshell, which, after closure, must be inserted with the maximal acoustictransparency into the anode-enhancer.

The third additional feature consists in that at least that part of theanode-enhancer, which is directed to the plasma cathode, is spheroidallyformed prior to mounting in the RVD. This allows the mechanicalsoliton-like impulse of density to be concentrated in a microscopicallysmall volume and, as a result of this concentration, to provide theimpact compression of an each target substance up to a superdense statewith a yield of 10¹⁷ to 10¹⁸ atoms of transmuted products even with theminimum (the order of 300-1000 J) energy consumption for a single‘shot’.

The fourth additional feature consists in that the target is formed inthe shape of a spheroidal body tightly fixed inside the anode-enhancerin such a way that the centers of the inner and outer spheroidspractically coincide. This allows to increase essentially the yield of atransmuted material.

The fifth additional feature consists in that the anode-enhancer isacted upon by an electron beam having the electron energy up to 1.5 MeV,current density not greater than 10⁸ A/cm² and duration not greater than50 ns. These parameters are sufficient for pycnonuclear processes toproceed in targets consisting of the most stable atoms of chemicalelements from the ‘middle part’ of the periodic table.

The sixth additional feature consists in that the current density of theelectron beam is not more than 10⁷ A/cm², which is sufficient foreffective impact compression of the majority of condensed targetmaterials.

The seventh additional feature consists in that the residual pressure inthe RVD vacuum chamber is maintained at the level not greater than 0.1Pa, which is quite sufficient to prevent a gas discharge between the RVDelectrodes.

The second aspect of the problem is solved in that in a device forimpact compression of a substance, which is based on RVD and iscomprised of:

-   -   a strong gas-tight housing a part of which is made of a        current-conducting material shaped in axial symmetry to confine        a vacuum chamber, and    -   an axisymmetric plasma cathode and an axisymmetric        anode-enhancer mounted with a gap in the vacuum chamber        practically on the same geometric axis of which at least the        cathode is connected to a pulse high-voltage power source,        according to the invention    -   the plasma cathode is made in the form of a current-conducting        rod comprising a dielectric end element having the perimeter of        the rear end embracing the perimeter of said rod at least in the        plane perpendicular to the axis of symmetry of the cathode with        a continuous gap, and the area of the emitting surface being        greater than the maximum cross-section area of the        anode-enhancer,    -   at least one of the electrodes is provided with a means for        adjusting the gap between the electrodes, and    -   the distance from the common geometric axis of said plasma        cathode and anode-enhancer to the inner side of the        current-conducting wall of the vacuum chamber is greater than        50d_(max), where d_(max) is a maximum cross-sectional dimension        of the anode-enhancer.

The RVD having the combination of the mentioned features is useful atleast for transmutation of nuclei of certain chemical elements intonuclei of other chemical elements as it was disclosed above in thecommentaries to the subject matter of the method according to theinvention.

The first additional feature consists in that the current-conducting rodof the plasma cathode is pointed and the dielectric end element isprovided with an opening for setting on said rod the setting part ofwhich is located together with the pointed end inside the said opening.Such design makes it possible to stabilize the plasma cathode operationand at least partially to adjust the gap between the electrodes in theRVD by shifting the dielectric end element with respect to thecurrent-conducting rod.

The second additional feature consists in that the anode-enhancer has acircular shape in the cross section and is completely produced from acurrent-conducting in its main mass material to be transmuted. Thisallows to demonstrate the effect of transmutation on the simplestspecimens of pure metals and metal alloys and to product transuranidesin particular.

The third additional feature consists in that the anode-enhancer is madecomposite and comprises at least a one-layer solid shell and an insertedtarget tightly embraced by this shell, said target being in the shape ofa body of revolution and made of an arbitrary condensed material with adiameter in the range of (0.05-0.2)·d_(max), where d_(max) is a maximumcross-sectional dimension of the anode-enhancer. This allows to carryout the impact compression of a substance not only with the purpose oftransmutation of atomic nuclei but also with the purpose of producingenergy in the volume where pycnonuclear processes proceed withsubstantial (at least by an order) overshooting the Lawson criterion.

The fourth additional feature consists in that at least one shieldpreferably of current-conducting material is mounted in the tail part ofthe anode-enhancer. It can capture a portion of products of pycnonuclearprocesses produced as a result of the impact compression of the maintarget to a superdense state and function as an additional target fornuclear interaction at the scattering of transmuted particles of theanode-enhancer.

The fifth additional feature consists in that said shield is a thin-wallbody of revolution with the diameter not less than 5d_(max) which isspaced from the nearest to the plasma cathode end of said anode-enhancerby the distance up to 20d_(max), where d_(max) is a maximumcross-sectional dimension of the anode-enhancer. Such shield promotesself-focussing of the electron beam on the major portion of theanode-enhancer surface and captures a tangible portion of products ofpycnonuclear processes.

The sixth additional feature consists in that said thin-wall body ofrevolution has a flat or concave surface at the side of theanode-enhancer. This significantly retards precipitation of thepycnonuclear processes products on the vacuum chamber walls.

The third auxiliary aspect of the problem is solved in that in theaxisymmetric plasma cathode having a current-conductive rod forconnection to a pulsed high-voltage power source and a dielectric endelement according to the invention the perimeter of the rear end of thedielectric element embraces the perimeter of said rod with a continuousgap at least in the plane perpendicular to the axis of symmetry of thecathode.

In case of a breakdown along the surface, the dielectric end element ofsuch cathode is practically instantly covers with plasma. The electronwork function in such plasma is close to zero. Therefore, the current inthe RVD electrode intermediate gap and, respectively, the total electronenergy in the electron beam practically coincide with physicallypermissible maximum values of these parameters. That is why the plasmacathode of the invention is especially useful in RVD based devices forimpact compression of a substance.

The first additional feature consists in that the current-conducting rodof the plasma cathode is pointed and the dielectric end element isprovided with an opening for setting on said rod the setting part ofwhich is located together with the pointed end inside the said opening.As mentioned above, this makes it possible to use the plasma cathode atleast as one of means for adjusting the gap between the RVD electrodes.

The second additional feature consists in that the dielectric endelement has a blind opening, which is more preferable in adjusting thegap between the RVD electrodes.

The third additional feature consists in that the dielectric end elementhas a through opening, that is more preferable for controlling theformation of a plasma cloud and, respectively, stabilizing of the RVDoperation at the moment of breakdown.

The fourth additional feature consists in that the dielectric endelement is made of a material selected from the group consisting ofcarbon-chain polymers with single carbon-to-carbon bonds, paper-baselaminate or textolite type composite materials with organic binders,ebony wood, natural or synthetic mica, pure oxides of metals belongingto III-VII groups of the periodic table, inorganic glass, sitall,ceramic dielectrics and basalt-fiber felt.

This list of preferable materials allows selection of dielectrics takinginto account various requirements. For example, said organic materialsand basalt-fiber felt are useful in terms of convenience in producingdielectric end elements and handling them while adjusting the gapbetween the RVD electrodes, and the rest of the mentioned inorganicmaterials are useful in terms of wear resistance and minimum effect uponthe residual pressure in the RVD vacuum chamber after each next ‘shot’.

The fifth additional feature consists in that the dielectric end elementhas a developed surface to facilitate formation of a plasma cloud incase of a breakdown.

The sixth additional feature consists in that the minimumcross-sectional dimension of said dielectric element isC_(de min)=(5-10)·C_(cr max), and the length of said element isI_(de)=(10-20)·C_(cr max), where C_(cr max) is a maximum cross-sectionaldimension of the current-conducting rod. Such relative dimensions ofparts of the plasma cathode completely exclude the pinch in the RVDelectrode intermediate gap and ensure the electron beam self-focussingon a substantial part of the anode-enhancer.

It will be understood that:

-   -   In selection of specific embodiments of the invention, arbitrary        combinations of said additional features with the primary        inventive concept are possible,    -   This inventive concept can be supplemented and/or specified        within the scope defined by the claims using general knowledge        of those skilled in the art,    -   The preferable embodiments of the invention disclosed below are        in no way intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The essence of the invention will now be explained (in examples ofnuclei transmutation in pycnonuclear processes) by detailed descriptionof the device and method for compressing a substance by impact withreference to the accompanying drawings, in which:

FIG. 1 is a structural layout diagram of electrodes in the RVD, theadjustable geometric parameters being pointed out;

FIG. 2 is a block diagram of a pulsed high-voltage power source;

FIG. 3 is a preferable structure of an axisymmetric plasma cathode (asection along the symmetry axis);

FIG. 4 is a view of the rear end of the axisymmetric plasma cathodetaken along the plane IV-IV (with a cross section of thecurrent-conducting rod);

FIG. 5 is an integral axisymmetric anode-enhancer used directly as atarget for demonstration of impact compression of a substance to asuperdense state (a section along the symmetry axis);

FIG. 6 is a hollow-body axisymmetric anode-enhancer with an insertedspherical target designed, e.g., for at least partial transmutation oflong-lived radioactive isotopes of selected chemical elements intostable isotopes of as a rule other chemical elements (a section alongthe symmetry axis);

FIG. 7 is a graphic charts of voltage and current change in the RVDdischarge pulse;

FIG. 8 is a diagram of absolute (by weight %) distribution of chemicalelements according to the mass of atomic nuclei in products oftransmutation of chemically pure copper;

FIG. 9 is a diagram of relative distribution of the same chemicalelements according to the mass of atomic nuclei in products oftransmutation of chemically pure copper;

FIG. 10 is a diagram of absolute (by weight %) distribution of chemicalelements according to the mass of atomic nuclei in products oftransmutation of chemically pure tantalum;

FIG. 11 is a diagram of relative distribution of the same chemicalelements according to the mass of atomic nuclei in products oftransmutation of chemically pure tantalum;

FIG. 12 is a diagram of absolute (by weight %) distribution of chemicalelements according to the mass of atomic nuclei in products oftransmutation of chemically pure lead;

FIG. 13 is a diagram of relative distribution of the same chemicalelements according to the mass of atomic nuclei in products oftransmutation of chemically pure lead;

FIG. 14 is a reference mass spectrum of isotopes of nickel obtained by astudy of samples of natural nickel that coincides with the naturalabundance of such isotopes in the Earth's crust;

FIG. 15 is a mass spectrum of relative distribution of isotopes ofnickel in one of aggregates on a copper shield obtained in the result ofpycnonuclear processes in an integral copper target (specimen No. 1);

FIG. 16 is the same mass spectrum as in FIG. 15 obtained in a study ofanother aggregate of atoms of nickel on the same shield;

FIG. 17 is a microphotography of a product of impact compression of asubstance to a superdense state in the form of an iron hemisphere with aspherical cavity driven into a copper shield and partially etched by anion beam.

BEST MODE FOR CARRYING OUT THE INVENTION

The device according to the invention (FIG. 1) is made on the basis of aRVD. The essential parts thereof are:

-   -   a strong gas-tight housing 1 which is made partly from a        current-conducting material (for example, copper or stainless        steel) shaped axisymmetrically to confine a vacuum chamber        closed, in the operation condition, with a dielectric end cover        2 and connected when required via at least one pipe (not shown)        to a vacuum pump;    -   a non-consumable axisymmetric current-conducting rod 3        preferably circular in the cross section and preferably tapered        in the longitudinal section, rigidly and tightly fixed in the        cover 2 and intended for connection of RVD to a pulsed        high-voltage power source described below;    -   a replaceable (as worn out) axisymmetric plasma cathode        comprising:        -   a current-conducting rod 4 having its tail fixed in the rod            3 and        -   a dielectric end element 5 rigidly connected with the rod 4,            said element 5 having the area of the working end exceeding            the cross-section area of the rod 4;    -   an axisymmetric anode-enhancer 6 which can be either integral or        including a target 7, the maximum cross-section area of said        anode-enhancer being smaller than the area of the emitting        surface of the dielectric end element 5;    -   optionally, a shield 8 preferably of current-conducting material        is mounted on the tail part of the anode-enhancer 6;    -   at least one (not shown specially but denoted with pairs of        arrows under the contours of the plasma cathode 4, 5 and the        anode-enhancer 6) mean for adjusting a gap between the        electrodes, i. e. the space between the point of intersection of        the end surface of the dielectric element 5 of the plasma        cathode with its symmetry axis and similar point at the end of        the anode-enhancer 6 both lying practically along the same        geometric axis.

The RVD pulsed high-voltage power source (FIG. 2) in the simplest casecan be a well known to those skilled in the art system that includes atleast one capacitive or inductive energy storage with at least twoplasma (or other) current interrupters. However, preferable are ‘hybrid’sources of power (see, e.g., 1. P. F. Ottinger, J. Appl. Phys., 56, No.3, 1984; 2. G. I. Dolgachev et al. Physics of Plasma, 24, No. 12, p.1078, 1984) which comprise connected in series (FIG. 2):

-   -   an input transformer 9 with means for connection to an        industrial power network and a high-voltage output winding,    -   a storage LC-circuit 10 comprising suitable (not shown)        capacitors and inductors,    -   a unit 11 for plasma interruption of discharge current in the        LC-circuit comprising a set of well known to workers in the art        plasma guns symmetrically located in one plane, the number of        which (up to 12, in particular) usually being equal to the        number of capacitors in the LC-circuit.

Of course, besides of said power units, the RVD pulsed high-voltagepower sources usually incorporate means (not shown) for measuring pulsecurrent and voltage, such as at least one Rogovski belt and at least onecapacitive voltage divider.

A source of such type was used for the RVD supply in experiments oncompressing a substance by impact to a superdense state described below.This source could provide the following values of the controlledparameters:

-   -   Mean energy of beam electrons . . . 0.2 to 1.6 MeV    -   Electron beam duration . . . not greater 100 ns    -   Electron beam power . . . 2.10⁹ to 0.75-10¹² W    -   High-voltage discharge current . . . 10 kA to 500 kA.

For effective carrying out of the method of impact compression of asubstance, it is recommended to follow a number of additional conditionswhen producing individual parts of the RVD and targets.

Thus, it is important that the distance from the common geometric axisof the plasma cathode 4, 5 and anode-enhancer 6 to the inner side of thecurrent-conducting wall of the housing 1 exceed 50d_(max), where d_(max)is a maximum cross-sectional dimension of the anode-enhancer 6.

It is desirable that the plasma cathode (FIG. 3) has itscurrent-conducting rod 4 pointed and dielectric end element 5 providedwith a blind or through opening. This element 5 must be fitted on therod 4 with a slight tightness so that the setting part of the rod 4together with the pointed end be found inside said opening. The shape ofsuch opening in its cross-section and the cross-section of the rod 4(provided the conditions of axial symmetry be followed) may be notcircular (e.g., oval, elliptic, star-like, as shown in FIG. 4, etc.).

It is also desirable that the perimeter of the rear end of thedielectric element 5 (FIG. 4) at least in the plane perpendicular to thesymmetry axis of the plasma cathode embrace the perimeter of thecurrent-conducting rod 4 with a continuous gap. It is to be understoodthat this condition can be provided in various shapes of cross-sectionaloutline of the rod 4 and element 5.

It is highly preferable that the dielectric end element 5 of the plasmacathode have a developed outer surface, e.g., initially rough, as shownin FIG. 4, or deliberately corrugated at least in one arbitrarydirection. Particularly, element 5 can be used having a shape of anaxisymmetric multiple-pointed star in their cross-sections.

It is desirable that the minimum cross-sectional dimension C_(de min) ofsaid element 5 be in the range of (5-10)·c_(cr max), and the lengthI_(de) be in the range of (10-20)·c_(cr max), where c_(cr max) is amaximum cross-sectional dimension of the current-conducting rod 4.

Said element 5 of the plasma cathode can be made of any dielectricmaterial, which (at the chosen shape and dimensions) is capable for abreakdown under the chosen working voltage in the gap between the RVDelectrodes.

It is preferable that such material be selected from the groupconsisting of carbon-chain polymers with single carbon-to-carbon bonds(e.g., polyethylene, polypropylene etc.), paper-base laminate ortextolite type composite materials with organic binders, ebony wood,natural or synthetic mica, pure oxides of metals belonging to III-VIIgroups of the periodic table, inorganic glass, sitall, basalt-fiber feltand ceramic dielectrics.

As it was mentioned above, the axisymmetric anode-enhancer 6 can be:

-   -   either integral (FIG. 5) and consisting of an arbitrary solid        usually current-conducting in its mass preferably metallic        material (including both pure metals and their alloys), e.g.,        copper, tantalum, lead, etc.;    -   or have (FIG. 6) at least a one-layer preferably spherical shell        6 made of preferably current-conducting material and an        axisymmetric inserted target 7 tightly fixed in said shell and        made of an arbitrary condensed (solid or liquid) substance to be        compressed by impact.

A maximum diameter of the axisymmetric inserted target 7 is preferablyselected in the range of (0.05-0.2)·d_(max), where d_(max) is a maximumcross-sectional dimension of the anode-enhancer 6 as a whole.Irrespective of the geometric shape of the target 7 body, it must befixed inside the anode-enhancer 6 so that the center of its surfacecurvature practically coincide with the curvature center of the workingsurface of the anode enhancer 6. It is very important that dislocationdensity in the material of the anode-enhancer 6 and in the material ofthe target 7 be as small as possible and that an acoustic contact beprovided between these parts.

Said shield 8, which can be mounted in the tail part of theanode-enhancer 6, is usually made from a current-conducting material asa preferably thin-wall body of revolution. The diameter of said shield 8must be not smaller than 5d_(max) and it's distance from the working endof the anode-enhancer 6 must be not greater than 20d_(max), whered_(max) is a maximum cross-sectional dimension of the anode-enhancer 6.It is desirable that said shield 8 have a flat or concave surface at theside of the working end of the anode-enhancer 6 (FIGS. 5 and 6).

The method for impact compression a substance using the described deviceusually includes:

-   -   a) connecting the current-conducting rod 4 of the aforesaid        plasma cathode to the non-consumable current-conducting rod 3;    -   b) producing a set of replaceable axisymmetric anodes-enhancers        6 preferably having their working ends rounded in one of the        following variants:    -   either in the form of integral pieces of the material to be        compressed by impact (for transmutation or any other nuclear        transformation),    -   or in the form of preferably one-layer shells wherein targets 7        are tightly inserted, said targets being made of the material        (preliminarily encapsulated, as required) to be compressed by        impact (for transmutation or any other nuclear transformation);    -   c) (optionally) fitting at least some of the anodes-enhancers 6        with current-conducting shields 8 made of copper, lead, niobium,        tantalum etc.;    -   d) placing each next anode-enhancer 6 in the vacuum chamber of        the RVD housing 1 practically on the same geometric axis with        the plasma cathode 4, 5;    -   e) adjusting the gap between the working ends of the dielectric        end element 5 of the plasma cathode and the anode-enhancer 6 in        such a way that the center of curvature of the working surface        of the anode-enhancer 6 is located inside the focal space of the        collectively self-focussing electron beam at a pulse discharge        of the power source via the RVD;    -   f) closing the vacuum chamber by fitting the end dielectric        cover 2 on a flange of the strong gas-tight current-conducting        housing 1 of the RVD;    -   g) vacuuming the chamber in the RVD housing 1, which is carried        out:    -   at least twice prior to the first ‘shot’ upon the target        (pumping out the air first and then at least once blowing down        the chamber with clean dry nitrogen and re-vacuuming to the        residual pressure of gases not greater than 0.1 Pa), and    -   at least once prior to each next ‘shot’, if the residual        pressure exceeds said value;    -   h) connecting an external high-voltage power source of the RVD        to a power network via the input transformer 9 and storing the        electric energy required for an experiment in the LC-circuit 10;    -   i) discharging the LC-circuit 10 via the unit 11 for plasma        interruption of the current pulse, the non-consumable        axisymmetric current-conducting rod 3, the replaceable        current-conducting rod 4 and the dielectric end element 5 on the        RVD anode-enhancer 6 with generation of an electron beam having        the electron energy not less than 0.2 MeV, current density not        less than 10⁶ A/cm² (and preferably not more than 10⁸ A/cm², and        more preferably not more than 10⁷ A/cm²) and duration not        greater than 100 ns (and preferably not more than 50 ns);    -   j) removing of the products obtained after the compression of a        portion of the target substance to a superdense state from the        vacuum chamber of the RVD housing 1 and studying these products        by the commonly used techniques.

The experimental targets were intended to:

-   -   demonstrate the transmutation effect as a result of the impact        compression of a substance to a superdense state (integral        anodes-enhancers 6 in accordance with FIG. 5); and    -   evaluate the possibility of radioactive materials deactivation        (hollow-body anode-enhancers 6 with inserted target 7 according        to FIGS. 1 and 6). As mentioned above, such target 7 must be        inserted into the anode-enhancer 6 providing the maximum        acoustic transparency of their junction contact, and the        curvature centers of the working surfaces of the both said        components must coincide practically.

The integral anodes-enhancers 6 had average radius of curvature of theworking ends in the range of 0.2 to 0.5 mm, as a rule. They were made,particularly, of chemically pure metals, such as copper, tantalum andlead. Such anodes-enhancers 6 can be stored outdoors. An oxide film thatappears on the surface (especially of copper and lead) does not preventand, according to some observations, even enhances their use inaccordance with the above-mentioned purposes.

The inserted targets 7 had a shape of pellets made of available Co⁶⁰isotope and artificial mixtures of Co⁵⁶ and Co⁵⁸ produced by irradiationof natural nickel on U-120 cyclotron in Nuclear Research Institute ofNational Academy of Sciences of Ukraine.

The use of such targets required additional shells (not shown) made ofpolycaprolactam (capron) that are mounted inside the RVD vacuumchambers. These shells enveloped both RVD electrodes and reducedsignificantly the risk of the radioactive cobalt precipitation on thewalls of the housing 1 and the RVD cover 2.

The initial radioactivity values and those attained after transmutationof utilized cobalt isotopes were controlled by ordinarygermanium-lithium gamma-ray detectors.

More than thousand of adjustment experiments had been carried out priorto beginning of the operational experiments on impact compression of asubstance to a superdense state. The results of adjustment experimentshelped to select and more exactly define (taken into account thedimensions of parts 4,5 of the plasma cathode and anode-enhancer 6, andspecific parameters of the charge) the width of the gap between the RVDelectrodes in order to provide hitting of the target curvature centersinto the focal space of the RVD electron beam.

The operational experiments were carried out in series. Their numbervaried in different series and ranged from 50 (at transmutation ofradioactive cobalt) to several hundreds. All the experiments had athrough numbering.

The initial data on the used targets, discharge parameters and obtainedresults were recorded in logbooks under sequential numbers.

The shape of voltage and current pulses in the gap between the RVDelectrodes and actual duration of the electron beam were checked withcurrent and voltage oscillograms, typical examples are shown in FIG. 7.These and many other oscillograms demonstrate that the duration of theelectron beam does not exceed 100 ns.

It is important to note that the electron beam current (despite a sharpvoltage drop on the RVD plasma cathode) only slightly decreases ascompared to the peak value. This proves the efficiency of usage of theplasma cathodes 4,5.

After statistical processing of the results of the adjustmentexperiments with regard to the controlled parameters of the electronbeam generation process approximate dimensions for the electrodes gapand approximate values of the focal space volume were determined (seeTable 1). TABLE 1 Dependence of the gap between the electrodes and thefocal space volume on the rest of the parameters of the electron beamgeneration process Mean Dimensions of the Dimensions of the Gap energyof dielectric element of working end of the between Focal beam theplasma cathode, anode-enhancer the space electrons, mm Curvature Area,electrodes, volume, MeV Diameter Length radius, mm mm² mm mm³ 0.24.0-6.0 5.0 0.25 0.75 2.0-3.0 0.02 0.5 16.0-24.0 8.75 0.45 2.4  7.0-10.50.12 1.0 45.0-67.0 9.5 0.73 6.7 36.5-55.0 about 0.5 1.5  80.0-120.015.25 about 1.0 about 12.3 ≧59 about 1.3

Following these limits of the gap between the RVD electrodes in theoperational experiments ensured:

-   -   First, hit of the curvature centers of the working surfaces of        the integral anodes-enhancers 6 (and in case of using targets 7,        hit of the curvature centers of their surfaces too) into the        focal space of the collectively self-focussing electron beam and    -   Second, reveal of the effect of transmutation after each pulsed        discharge of the RVD power source.

Moreover, following the parameters listed in Table 1, the currentdensity on the surface of the working end of the anode-enhancer 6 waspossible to establish within the range of 10⁶ A/cm² to 10⁸ A/cm². Forthe most part of impact compression experiments, this parameter wasmaintained within the range of 10⁶ A/cm² to 10⁷ A/cm².

The results of all the operational experiments looked rather uniform,namely:

-   -   Products of transmutation in the form of a wide spectrum of        practically stable isotopes of various (both light and heavy,        and even super-heavy transuranides) chemical elements appeared        from a portion (at the average about 30% by weight) of the        initial material;    -   These products and chemically unchanged residues of integral        anodes-enhancers 6 (and inserted targets 7) flew apart from the        volume of impact compression primarily in the direction opposite        to the plasma cathode and precipitated as drop-shaped aggregates        of various forms and dimensions on the walls of the vacuum        chamber of the RVD and/or on the shields 8, if applicable.

Said products were collected for study.

Electron microprobe-analyzers REMMA-102, Tesla and Cameca were used fordetecting of separated aggregates of transmutation products anddetermination of their position on the surface (on shields 8 inparticular) with the purpose of subsequent study of the elemental andisotopic composition (and in certain cases, for registration of theshape of such aggregates). Jamp10S model of an Auger spectrometer byJEOL, time-of-flight pulsed laser mass-spectrometer designed by Kiev'sNational T. G. Shevchenko University (Ukraine), ionicmicroprobe-analyzer CAMECA's IMS-4f and FINNIGAN's highly sensitivemass-spectrometer VG9000 were used for the study of the elemental andisotopic composition of said products.

As a result in all the operational experiments on impact compression ofintegral anodes-enhancers 6 to a superdense state, an essentialdiscrepancy was observed between their initial composition (practicallyone chemical element for all targets in each series) and elemental andisotopic composition of the transmutation products.

In order to make certain of that, let's observe FIGS. 8 to 13 whereinvertical dash lines indicate the charge of an initial chemical element'snucleus.

It should be noted, that the isotopes of chemical elements which werenot present in the initial material of the target but appeared in theproducts of transmutation are indicated in FIGS. 8, 10 and 12:

-   -   by light circles according to their concentration in said        products of pycnonuclear processes,    -   by black squares according to their concentration in the Earth's        crust.

Nuclei charges and percentage by weight of these isotopes are easy todetermine using the numerical data on the X and Y axis respectively.

With light triangles and adjacent chemical symbols, FIGS. 9, 11 and 13show relative deviations Y of concentrations (% by weight) of certainchemical elements from natural abundance ratio that were calculated byformula: ${\frac{A - B}{A + B} = Y},{{where}\text{:}}$

-   -   A is a ratio of a certain isotope of a certain chemical element        in the products of transmutation, and    -   B is a ratio of the same isotope of the same chemical element in        the Earth's crust.

As it's clearly seen from FIGS. 8, 10 and 12, in the process oftransmutation of initial copper, tantalum and lead appears a widespectrum of isotopes of various chemical elements with smaller andgreater Z nuclear charges in comparison to the nuclear charge of parentelement.

However, the greater is the nuclear charge of the target material thehigher is the probability of production of stable transuranides(including those not identified yet) with atomic mass of greater than250 atomic mass units (and in some to be checked cases, up to 600 amuand greater).

The presence of atoms having such masses was detected at first by themethod of ion mass spectrometry and then was proved by well knownmethods of Rutherford alpha and proton back-scattering.

Moreover, FIGS. 9, 11 and 13 clearly show that concentrations ofsubstantial portion of chemical elements in transmutation productsstatistically reliably exceed (more than in three times and someelements in 5-10 and more times) their normal concentrations in theEarth's crust (see areas marked out with dark colour within the range ofY values from 0.5 to 1.0). This obviously proves the artificial originof such products of pycnonuclear processes.

As for changes in elemental and isotopic composition, similar resultswere obtained also in experiments with targets of radioactive cobalt.However, in these cases the main attention was paid to reduction inradioactivity in products of the target spread due to transmutation ofradioactive nuclei of cobalt into non-radioactive isotopes of otherchemical elements, in those part of the target which was in the focalspace.

This reduction essentially varied in separate samples, that can beexplained by difference in density of acoustic contact between the innerwalls of cavities in anodes-enhancers and the material of insertedtargets 7 (see data from a log-book in Table 2). TABLE 2 Radioactivityreduction in the products of cobalt targets spread Reduction inReduction in Reduction Sample gamma- Sample gamma- Sample in gamma-number activity, % number activity, % number activity, % 2397 47.6 24792.2 2588 46.5 2398 10.7 2481 22.8 2600 33.3 2425 21.6 2534 29.5 276928.9 2426 17.0 2558 22.9 2770 36.4

Thus, sample No. 2479 was deactivated only by 2.2% whereas sample No.2397 and No. 2588 lost more than 45% of their activity in the result oftransmutation.

Further, as it was definitely established, the distribution of isotopesin conglomerates of atoms of each chemical element detected in productsof pycnonuclear processes is essentially differed from the distributionof the same isotopes in the Earth's crust.

The brightest example of such drastic discrepancy is the differencebetween the normal distribution of isotopes of nickel in natural samples(FIG. 14) and in two aggregates of nickel atoms produced bytransmutation of copper targets (FIGS. 15 and 16). Thus, the content ofNi⁵⁸ isotope is up to 70% in the mass of natural nickel, while theproportion of Ni⁵⁸ in products of copper transmutation (with Cu⁶³isotope dominating in the target) exceeds 10%. Similarly, content ofNi⁶⁰ isotope essentially (usually twice) decreased whereas content ofNi⁶² sharply increased.

And at last, a bright evidence of impact compression of a substance to asuperdense state by the method according to the invention is an ejectionfrom the RVD focal space rather big bodies whose shape visually provesthe existence of necessary conditions for a short-term appearance of atleast electron-nuclear and, even, electron-nucleonic plasma in saidspace.

Thus, on FIG. 17, presented essentially iron hemisphere comprising 93%by weight Fe with admixtures of silicon and copper isotopes on thebackground of the copper shield.

Obviously, this hemisphere is a fraction of a spherical body formed froma substantial part of the copper anode-enhancer 6 (sample No. 4908according to the log-book of the applicant). It has an outer diameterabout 95 μm and a practically concentric spherical cavity with adiameter of about 35 μm. The roughness on the major portion of the ringend of the hemisphere can be explained by the crack of the initialsphere.

It is easy to assume that in the experiment with the sample No. 4908,the center of the focal space of the electron beam practically coincidedwith the center of the target curvature. In this case, soliton-likedensity impulse focussed itself in the volume that is represented as aspherical cavity in the disclosed product.

INDUSTRIAL APPLICABILITY

The device for compressing a substance by impact may be produced usingcommercially available components, and the method according to inventionmay be a basis for development and implementation of highly efficientand environmentally safe technologies for:

-   -   First, synthesis of stable transuranides, which is greatly        important for broadening the knowledge about the nature;    -   Secondly, transmutation of nuclei of known chemical elements for        experimental production of their stable isotopes and for        neutralization of radioactive materials (including        atomic-industry waste) containing long-lived radioactive        isotopes; and    -   Third, ICF using chemical elements widely spread in nature and        their compositions as fuel.

1-22. (canceled)
 23. A method of compressing a substance by impactutilizing a relativistic vacuum diode having an axisymmetric vacuumchamber with current-conducting walls, an axisymmetric plasma cathodeand an axisymmetric anode-enhancer, including: producing a target in theshape of an axisymmetric part made of a condensed substance thatfunctions as at least a part of the anode-enhancer, producing a plasmacathode in the form of a current-conducting rod comprising a dielectricend element having the perimeter of the rear end embracing the perimeterof said rod at least in the plane perpendicular to the axis of symmetryof the cathode as the whole with a continuous gap, and the area of theemitting surface being greater than the maximum cross-section area ofthe anode enhancer, placing said cathode inside the vacuum chamber ofthe relativistic vacuum diode in such position that the axes of symmetryof this cathode and this vacuum chamber practically coincide, placingthe anode-enhancer in the vacuum chamber of the relativistic vacuumdiode practically on the same geometric axis with the plasma cathodewith such a gap that the center of curvature of the working surface ofthe anode-enhancer is located inside the focal space of the collectivelyself-focusing electron beam pulse discharge of a high-voltage powersource via the relativistic vacuum diode to generate an electron beamwith an electron energy not smaller than 0.2 MeV, and acting upon thesurface of the anode-enhancer by said beam in an electron collectivelyself-focussing mode with the current density not smaller than 10⁶ A/cm²and pulse duration not greater than 100 ns.
 24. A method as defined inclaim 23, wherein used in the relativistic vacuum diode plasma cathodehas a pointed current-conducting rod, the dielectric end element of thiscathode is provided with an opening for setting on said rod, and thesetting part of said rod together with the pointed end is located insidethe opening.
 25. A method as defined in claim 23, wherein the target isformed in the shape of an insert into the central part of the RVDanode-enhancer, the diameter of said insert is chosen in the range of0.05 to 0.2 of the maximum cross-sectional dimension (d_(max)) of theanode-enhancer.
 26. A method as defined in claim 23, wherein at leastthat part of the anode-enhancer, which is directed to the plasmacathode, is spheroidally formed prior to mounting in the relativisticvacuum diode.
 27. A method as defined in claim 25, wherein the target isformed in the shape of a spheroidal body tightly fixed inside theanode-enhancer in such a way that the centers of the inner and outerspheroids practically coincide.
 28. A method as defined in claim 23,wherein the anode-enhancer surface is acted upon by an electron beamhaving the electron energy up to 1.5 MeV, current density not greaterthan 10⁸ A/cm² and duration not greater than 50 ns.
 29. A method asdefined in claim 28, wherein the current density of the electron beam isnot greater than 10⁷ A/cm².
 30. A method as defined in claim 23, whereinthe residual pressure in the vacuum chamber of the relativistic vacuumdiode is maintained at the level not greater than 0.1 Pa.
 31. A devicefor impact compression of a substance, which is based on relativisticvacuum diode and is comprised of: a strong gas-tight housing a part ofwhich is made of a current-conducting material shaped in axial symmetryto confine a vacuum chamber, and an axisymmetric plasma cathode in theform of a current-conducting rod with a dielectric end element havingthe perimeter of the rear end embracing the perimeter of said rod atleast in the plane perpendicular to the axis of symmetry of said cathodewith a continuous gap, an axisymmetric anode-enhancer at least a part ofwhich is designed to be a target for impact compression, saidanode-enhancer having the maximum cross-section area smaller than thearea of the emitting surface of said cathode and being mounted in saidvacuum chamber with a gap practically on the same geometric axis of withsaid cathode, and a pulsed high-voltage power source connected at leastto said plasma cathode, at least one of said relativistic vacuum diodeelectrodes being provided with means for adjusting the gap between theelectrodes, and the distance from the common geometric axis of saidelectrodes to the inner side of the current-conducting wall of saidvacuum chamber being greater than 50d_(max), where d_(max) is a maximumcross-sectional dimension of the said anode-enhancer.
 32. A device asdefined in claim 31, wherein the current-conducting rod of said plasmacathode is pointed and the dielectric end element thereof is providedwith an opening for setting on said rod the setting part of which islocated inside said opening together with the pointed end.
 33. A deviceas defined in claim 31, wherein said anode-enhancer has a circular shapein the cross section and is completely produced of a material to betransmuted that is current-conducting in its main mass.
 34. A device asdefined in claim 31, wherein said anode-enhancer is made composite andcomprises at least a one-layer solid shell and an inserted targettightly embraced by this shell, said target being in the shape of a bodyof revolution and made of an arbitrary condensed material with adiameter within the range of (0.05-0.2)d_(max), where d_(max) is amaximum cross-sectional dimension of the anode-enhancer.
 35. A device asdefined in claim 31, wherein at least one shield preferably ofcurrent-conducting material is mounted in the tail part of saidanode-enhancer.
 36. A device as defined in claim 35, wherein said shieldis a thin-wall body of revolution with the diameter not less than5d_(max) which is spaced from the nearest to the plasma cathode end ofsaid anode-enhancer by the distance up to 20 d_(max), where d_(max) is amaximum cross-sectional dimension of the anode-enhancer.
 37. A device asdefined in claim 36, wherein said thin-wall body of revolution has aflat or concave surface at the side of said anode-enhancer.
 38. Anaxisymmetric plasma cathode for the relativistic vacuum diode having acurrent-conductive rod for connection to a pulsed high-voltage powersource and a dielectric end element, the perimeter of the rear end ofsaid dielectric element embraces the perimeter of said rod with acontinuous gap at least in the plane perpendicular to the axis ofsymmetry of the cathode.
 39. A cathode as defined in claim 38, whereinsaid current-conducting rod is pointed and said dielectric end elementis provided with an opening for setting on said rod the setting part ofwhich is located together with the pionted end inside the said opening.40. A cathode as defined in claim 39, wherein said dielectric endelement has a blind opening.
 41. A cathode as defined in claim 39,wherein said dielectric end element has a through opening.
 42. A cathodeas defined in claim 38, wherein said dielectric end element is made of amaterial selected from the group consisting of carbon-chain polymerswith single carbon-to-carbon bonds, paper-base laminate or textolitetype composite materials with organic binders, ebony wood, natural orsynthetic mica, pure oxides of metals belonging to III-VII groups of theperiodic table, inorganic glass, sitall, basalt-fiber felt and ceramicdielectrics.
 43. A cathode as defined in claim 38, wherein saiddielectric end element has a developed surface.
 44. A cathode as definedin claim 39, wherein said dielectric end element has a developedsurface.
 45. A cathode as defined in claim 40, wherein said dielectricend element has a developed surface.
 46. A cathode as defined in claim38 wherein said minimum cross-sectional dimension of said dielectricelement is c_(de min)=(5-10)c_(cr max), and the length of said elementis I_(de)=(10-20)c_(cr max), where c_(cr max) is a maximumcross-sectional dimension of the current-conducting rod.
 47. A cathodeas defined in claim 39 wherein said minimum cross-sectional dimension ofsaid dielectric element is c_(de min)=(5-10)c_(cr max), and the lengthof said element is I_(de)=(10-20)c_(cr max), where c_(cr max) is amaximum cross-sectional dimension of the current-conducting rod.